i didn’t think i’d be able to change it, but a lot of googling and staring at the code, have finally led me to a modest improvement in our zoom quality
check out these 2 comparison images, which are both at 75% zoom level
the uglier one is the current/old way, while the more cleaned up one is the new way
i should also mention that the sea zone borders never disappear if you turn map details “off”, however they sometimes disappear when you zoom with map reliefs on. i’m going to try making an option to draw them on top of the map reliefs so solve this issue.

